1. Field of the Invention
The present invention relates to a reuseable write enable/disable indicator, and more particularly, to a write enable/disable tab on a tape cassette, particularly a video tape cassette, which can be positioned to prevent recording of video or audio signals on the tape cassette.
2. Description of the Related Art
Audio and video signals are conventionally recorded on tape cassettes by accessing a magnetic tape through an opening on one side (or front) of the cassette. On the opposite side (or rear) of the cassette, one or two (in the case of audio cassettes) write enable tabs are located. These tabs are conventionally formed as an integral part of the cassette shell, but are attached on only one side of a rectangle. The location and size of the tab, as well as the distance the tab may bend in response to a specific force, like other dimensions and specifications of video tape cassettes are determined by industry standards. Examples of typical video tape cassettes can be found in U.S. Pat. Nos. 4,173,319 and 4,484,248. A sensing mechanism is included in most tape cassette recording equipment to sense whether the write enable tab is in place on the cassette inserted into the recording equipment. When it is desired to prevent accidental erasure of a tape's contents, the conventional tab or tabs on the tape cassette are bent and broken off.
As a result, if it is subsequently decided to record over the contents of the tape, which typically is a frequent occurrence, it is necessary to place a piece of tape over the opening(s) in the cassette shell so that the sensing mechanism in the recording equipment does not sense any opening in the cassette shell. This is a cumbersome process which doesn't always work. For example, the sensing mechanism may push the tape into the opening. In addition, the procedure may need to be repeated fairly often if the tape used to cover the opening loses its adhesiveness and falls off the cassette shell. If this occurs while the cassette is in recording or playback equipment, an additional drawback arises from the possibility of the loosened tape damaging the recording or playback equipment.
As described above, the conventional technique for indicating "write disable" of a tape cassette is both awkward and relatively permanent. Thus, it is likely that when only a temporary "write disable" is desired, the write enable tab is left in place and the possibility of erasure of the tape's contents becomes an accepted risk.